<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        img{
            width: 300px;
        }
    </style>
</head>
<body>
    <button id="ldh">刘德华</button>
    <button id="zxy">张学友</button>
    <img src="./ldh.jpg" alt="">
<script>
var ldh = document.getElementById('ldh');
var zxy = document.getElementById('zxy');
var img = document.querySelector('img');
 zxy.onclick = function(){
     img.src = './zxy.jpg';
 }
 ldh.onclick = function(){
     img.src = './ldh.jpg';
 }

 </script>

</body>
</html>